1. Field of the Invention
This invention relates generally to an elevator emergency LED lighting power supply assembly for providing backup power to one or more LED lamps of an elevator interior illumination system.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Emergency elevator lighting systems are known in the art. For example, U.S. Pat. No. 4,056,757 issued Nov. 1, 1997 to Mauch, discloses an elevator emergency lighting power supply assembly including a battery connected to lamps normally used for interior illumination of an elevator cab and an inverter connected between the battery and the lamps to provide AC power to the lamps. However, an elevator emergency lighting power supply assembly constructed according to the Mauch patent would be unable to power LEDs and would likewise be unable to power LED drivers or any other circuit elements arranged to rectify AC power output from the inverter.
It's also known to use light emitting diodes (LEDs) for display indicators as well as for area illumination in elevators, and for LED drivers to be used in conditioning power to be supplied to LEDs. Because LEDs need controlled current flowing to them, LED drivers are typically configured to rectify AC power received from primary AC power supply grids, into DC power of suitable voltage and current. LED drivers may also be configured to automatically ramp up their voltage output when additional LEDs are connected, while holding current output constant.